JP3454970B2 - Mask pattern correction method, pattern formation method, and photomask - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern correction method, and more particularly to a mask pattern correction method, a pattern formation method and a photomask for suppressing the optical proximity effect and the etching density effect.

[0002]

2. Description of the Related Art When reducing a device pattern, it is necessary to transfer a fine pattern according to a design pattern onto a wafer with high accuracy. However, even if the mask pattern formed according to the design pattern is used, the line width may deviate from the mask pattern due to various factors when the mask pattern is transferred onto the wafer.

For example, Japanese Patent Application Laid-Open No. 3-36549 discloses that the amount of resist that dissolves in a developing solution when developing a resist varies depending on the pattern density, and thus a line width shift occurs. That is, when the pattern density is small, the resist amount increases and the developing speed decreases, so that the pattern dimension becomes thick, and conversely, when the pattern density is large, the pattern dimension becomes thin.

In order to prevent such a line width deviation phenomenon due to a change in development speed, it is proposed in the pattern forming method disclosed in Japanese Patent Laid-Open No. 3-36549 that the dimensions of the mask pattern are corrected according to the pattern density. is doing.

[0005]

However, although the dimensional deviation due to the influence of the developing speed is being suppressed with the recent technological innovation, a new problem is caused by the further high integration of the semiconductor device. One of them is the phenomenon of line width deviation due to the optical proximity effect. The optical proximity effect is a phenomenon in which light passing through a mask pattern interferes with each other when adjacent patterns come close to each other, and the light intensity between the patterns changes. Therefore, when the patterns exist so close to each other that the optical proximity effect occurs, there is a problem that the line width of the formed resist pattern deviates from the design value.

Further, when etching a base using a resist pattern as a mask, there is a problem that a phenomenon in which an etching shift amount varies depending on the density of the resist pattern, that is, a so-called etching density effect occurs. Therefore,
The final pattern line width formed after etching is deviated from the design pattern due to both the optical proximity effect and the etching density effect. However, conventionally, there is no method for correcting such dimensional deviation, and qualitative and quantitative corrections have not been performed, so that there is a problem that the characteristic yield of the device is deteriorated.

An object of the present invention is to provide a mask pattern correcting method, a pattern forming method and a photomask for suppressing the dimensional deviation due to the optical proximity effect and the etching density effect.

[0008]

The above object is to provide a mask pattern correction method for a photomask used when projecting and exposing a pattern on a substrate, in which a first photomask is adjacent to the photomask with a certain distance. in forming a mask pattern and a second mask pattern, an optical proximity effect and effects
Dimensional deviation and pattern pitch
The pattern correction data is created using the relationship of
The mask pattern correction method is characterized in that the side of the mask pattern is moved based on a correction amount according to the distance between the first mask pattern and the second mask pattern.

Further, the above-mentioned object is, in a mask pattern correction method of a photomask used when projecting and exposing a pattern on a substrate, a first mask pattern and a first mask pattern adjacent to the first mask pattern on the photomask. Optical proximity when forming the second mask pattern arranged in parallel
Deviation and pattern due to the effect of etching and the density of etching
Create pattern correction data using the relationship with pitch,
A first side of the first mask pattern located on the second mask pattern side, and / or a second side of the first mask pattern located on the opposite side of the first side,
The present invention can also be achieved by a mask pattern correction method characterized by moving based on a correction amount according to the distance between the first mask pattern and the second mask pattern.

In the above mask pattern correction method, the distance between the first mask pattern and the second mask pattern is an average distance between the first mask pattern and the second mask pattern. Is desirable. Further, in the above mask pattern correction method,
It is preferable that the area on the photomask is divided into areas in which the correction amount of the mask pattern is substantially equal, and the mask pattern is corrected in each of the divided areas.

In the above mask pattern correction method, the correction amount includes a step of transferring a resist pattern onto the substrate using the photomask, and a step of etching the substrate using the resist pattern as a mask. It is desirable to obtain the dimensional deviation that occurs in (1) by measuring in advance as a function of the mask pattern interval.

It is also achieved by a photomask having a mask pattern corrected by the above mask pattern correction method. Also, on the substrate,
A pattern forming method for transferring a mask pattern formed on a photomask can also be achieved by a pattern forming method including an exposure step of exposing using the above-mentioned photomask.

Further, the above-mentioned object is, in a pattern forming method of exposing a resist film formed on a substrate by using a particle beam, on the substrate, a first pattern and a portion adjacent to the first pattern. When exposing the arranged second pattern, the dimension due to the optical proximity effect and the etching density effect is obtained.
Pattern correction using the relationship between legal deviation and pattern pitch
Data is created, and the side of the first pattern is
And a pattern forming method characterized by exposing the substrate with a particle beam using exposure data that is moved based on a correction amount according to the distance between the pattern and the second pattern. It

It is also achieved by a photomask having a mask pattern formed by the above pattern forming method.

[0015]

According to the present invention, when the first mask pattern and the second mask pattern arranged adjacent to the first mask pattern are formed on the photomask, optical proximity is provided.
Deviation and pattern due to the effect of etching and the density of etching
Create pattern correction data using the relationship with pitch ,
Since the side of the first mask pattern is moved based on the correction amount according to the distance between the first mask pattern and the second mask pattern, deviation of the pattern dimension due to the optical proximity effect or the etching density effect is prevented. can do.

Further, when the first mask pattern and the second mask pattern arranged adjacent to the first mask pattern are formed on the photomask, an optical proximity effect is generated.
Dimensional deviation due to etching density effect and pattern pitch
And a first mask located on the side opposite to the first side of the first mask pattern located on the side of the second mask pattern. Since the second side of the pattern is moved based on the correction amount according to the distance between the first mask pattern and the second mask pattern, it is possible to prevent the deviation of the pattern dimension due to the optical proximity effect or the etching density effect. You can

Further, if the second side is moved or the correction amount is divided into the first side and the second side to move, it is possible to prevent the interval between patterns due to the mask pattern correction from becoming narrow. Therefore, it is possible to prevent the resolution between patterns from deteriorating. In addition, in the above-described mask pattern correction method, if the first side or the second side is moved based on the correction amount according to the average distance between the first mask pattern and the second mask pattern, the two sides are adjacent to each other. Even when the mask patterns to be used are not parallel to each other, the mask patterns can be corrected.

Further, if the area on the photomask is divided into areas where the correction amount of the mask pattern is substantially equal and the mask pattern is corrected for each of the divided areas, the mask pattern can be accurately corrected. Further, in the above mask pattern correction method, the correction amount is determined by the masking of the dimensional deviation caused in the step of transferring the resist pattern onto the substrate using a photomask and the step of etching the substrate using the resist pattern as a mask. It can be obtained by measuring in advance as a function of the pattern interval.

Further, if the pattern is transferred onto the substrate by using the photomask having the mask pattern corrected by the above mask pattern correction method, it is possible to prevent the deviation of the pattern dimension due to the optical proximity effect and the etching density effect. it can. Further, in a pattern forming method for transferring a mask pattern formed on a photomask on a substrate, if the photomask is used for exposure, a pattern with a small change in dimension due to an optical proximity effect or an etching density effect is formed. can do.

The first pattern and the first pattern are formed on the substrate.
Of the second pattern arranged adjacent to the pattern of No. 2 by the optical proximity effect and the etching density effect.
Pattern compensation is performed using the relationship between the dimensional deviation and the pattern pitch.
If the positive data is created and the side of the first pattern is exposed using the exposure data moved based on the correction amount according to the distance between the first pattern and the second pattern, the electron beam It can also be applied to a pattern forming method using a particle beam such as.

Further, if the pattern is transferred by a photomask having a mask pattern formed by the above-mentioned pattern forming method, it is possible to form a pattern having a small dimensional deviation from the design dimension due to the optical proximity effect, the etching density effect and the like. .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mask pattern correcting method, a photomask and a pattern forming method according to an embodiment of the present invention will be described with reference to FIGS. First, the change in pattern due to the optical proximity effect will be described. Figure 1 shows 0.3
6 is a graph obtained by simulating a light intensity distribution on a wafer when a mask pattern having a width of 5 μm is exposed using a photomask arranged at a pitch of 0.8 μm or a pitch of 1.5 μm.

The value on the horizontal axis (μA) is about 0.078 by simulation, but the value is rounded to the second decimal place. In the figure, the solid line shows the case where a photomask having a pitch of 0.8 μm is used, and the broken line shows the case of 1.5 μm
The case where a pitch photomask is used is shown. Here, in order to make it easier to compare the light intensity curve when a photomask with a pitch of 1.5 μm is used with the curve with a pitch of 0.8 μm, the central portion of the curve of the light transmitting portion is omitted and the position of the mask pattern is It is drawn to match.

The pitch referred to in the specification of the present application means a repeating period of a mask pattern, for example, 0.35 μm.
When the width mask patterns are formed with a pitch of 0.8 μm, the distance between the mask patterns is 0.45.
μm. Further, since a recent projection apparatus generally performs reduction projection exposure, a mask pattern is drawn with a size about 5 times as large as a device pattern.
For convenience of explanation, the size of the mask pattern is indicated by the size of the finished product on the wafer.

As shown in FIG. 1, it can be seen that when the pitch of the mask pattern is narrowed from 1.5 μm to 0.8 μm, the spread of the light intensity peak of the light transmitting portion becomes large. When the peak of the light intensity distribution is widened in this way, the light intensity between the mask patterns increases. As a result, the line width of the transferred resist pattern becomes thin and at the same time the resist pattern interval is widened.

When the optical proximity effect occurs in this way, light is interfered by adjacent patterns, and it becomes difficult to transfer a resist pattern as designed. Next, the pattern change due to the etching density effect will be described with reference to FIGS. 2 and 3 are views showing the structure of a measurement pattern used when measuring the etching density effect.

As shown in FIG. 2A, the silicon substrate 1
A silicon oxide film 12 having a thickness of about 5 nm is formed on
When the silicon nitride film 14 having a thickness of about 115 nm is formed on the silicon oxide film 12, the silicon nitride film 14
The so-called LOCOS mask nitride film patterning process for patterning will be described as an example. A resist pattern 16 having a 0.35 μm wide isolated line pattern as shown in FIG. 2B and a 0.35 μm wide blank pattern as shown in FIG. 2C is formed on the substrate. The line width of the silicon nitride film 14 after etching was measured. With the blank pattern, it is possible to measure an effect corresponding to the case of etching a dense pattern in which the patterns are densely arranged.

Table 1 shows the difference between the etching shift amount when the silicon nitride film 14 is etched and the etching shift amount between the isolated line pattern and the blank pattern. In addition,
The etching shift amount is the difference between the line width of the resist pattern 16 and the line width of the patterned silicon nitride film 14. Further, these values are given a plus sign when the patterned silicon nitride film 14 is thicker than the line width of the resist pattern 16, and when the patterned silicon nitride film 14 is thinner than the line width of the resist pattern 16. A minus sign is attached.

[0029]

[Table 1] As shown in Table 1, the line width of the silicon nitride film 14 increases in the isolated line pattern, and the line width of the silicon nitride film 14 decreases in the blank pattern. That is, the etching shift amount changes depending on whether the pattern is rough or dense. Table 2 shows the amount of etching shift in the same structure when only the etching conditions are changed.

[0030]

[Table 2] As shown in Table 2, the absolute amount of the etching shift amount can be reduced by changing the etching conditions, but it is understood that the difference in the shift amount due to the difference in the pattern density still exists. Next, as shown in FIG.
A silicon oxide film 1 having a thickness of 8 nm is formed on the silicon substrate 10.
2, an α-silicon (amorphous silicon) film 18 having a film thickness of 50 nm, a WSi film 20 having a film thickness of 150 nm, a silicon oxide film 22, and α-C (amorphous carbon)
In the gate structure in which the film 24 and the
The result of patterning the -C film 24 and the silicon oxide film 22 will be described.

On the above substrate, an isolated line pattern as shown in FIG. 3 (b) and an L / S as shown in FIG. 3 (c).
A resist pattern 16 having a pattern (line and space pattern) was formed, and the line widths of the patterned α-C film 24 and the silicon oxide film 22 were measured after etching. Tables 3 and 4 show that the film thickness of the α-C film 24 is 1
30 nm, the thickness of the silicon oxide film 22 is 60 nm,
A resist pattern 16 having an L / S pattern in which an isolated line pattern having a width of 0.5 μm and a line pattern having a width of 0.5 μm is arranged at a pitch of 1 μm is formed, and an α-C film 24 patterned after etching is formed. It is the result of measuring the line width of the silicon oxide film 22. Tables 3 and 4 differ only in the etching conditions.

[0032]

[Table 3]

[0033]

[Table 4] Table 5 shows that the α-C film 24 has a film thickness of 32 nm, the silicon oxide film 22 has a film thickness of 60 nm, and an isolated line pattern having a width of 0.34 μm and a line pattern having a width of 0.34 μm at a pitch of 0.8 μm are shown. This is a result of forming the resist pattern 16 having the arranged L / S pattern and measuring the line widths of the patterned α-C film 24 and the silicon oxide film 22 after etching.

[0034]

[Table 5] Table 6 shows that the film thickness of the α-C film 24 is 32 nm, the film thickness of the silicon oxide film 22 is 60 nm, and the isolated line pattern having a width of 0.5 μm and the line pattern having a width of 0.5 μm at a pitch of 1.0 μm. This is a result of forming the resist pattern 16 having the arranged L / S pattern and measuring the line widths of the patterned α-C film 24 and the silicon oxide film 22 after etching.

[0035]

[Table 6] As shown in Tables 3 to 6, the etching shift amount changes depending on the resist pattern 16, the underlying structure, and the etching conditions, but under any of the conditions, the pattern line width formed by the increase in the pattern density is relatively large. Is decreasing.

As described above, it can be seen that in any structure, the etching shift amount changes as the pattern density changes. When the base is etched using the resist pattern 16 as a mask, such an etching density effect occurs, so that a line width shift occurs in the etching process. Therefore, the line width of the final pattern includes the line width deviation due to the optical proximity effect and the line width deviation due to the etching density effect.

In view of the above points, the inventors of the present invention have come to the idea of predicting the line width deviation due to the optical proximity effect and the etching density effect and then correcting the mask pattern. The details will be described below. For convenience of description, the dimensional deviation referred to in the present specification is defined as follows.

As shown in FIG. 4 (a), the resist pattern width when exposed using an isolated line pattern having a width W _MASK sufficiently isolated from other patterns so that the optical proximity effect does not occur is W _{RESIST. i} , the underlying pattern width after etching is W _ETCH.i, and the resist pattern width when exposed using two line patterns having a width W _MASK arranged in parallel as shown in FIG. 4B. When W _RESIST.P and the underlying pattern width after etching are W _ETCH.P , the dimensional deviation due to the optical proximity effect is expressed as W _RESIST.P −W _RESIST.i . In addition, the dimensional deviation due to the optical proximity effect and the etching density effect is expressed as W _ETCH.P- W _ETCH.i.

Next, the relationship between the dimensional deviation and the pattern pitch will be described. FIG. 5 is a graph showing the relationship between the dimensional deviation due to the optical proximity effect and the pattern pitch, FIG. 6 is a diagram showing the measurement pattern used when measuring the line width of the pattern, and FIG. 7 is the optical proximity effect and the etching density effect. 7 is a graph showing the relationship between the dimensional deviation due to and the pattern pitch.

As the substrate, a silicon substrate in which a gate oxide film and a polycrystalline silicon film were sequentially laminated was used, and a line pattern having a width of 0.25 μm was formed on this substrate. A KrF excimer stepper having an NA of 0.5 and a of 0.5 was used for the exposure, and a positive resist was patterned. Further, the measurement pattern shown in FIG. 6 was used for measuring the width of the resist pattern, and measurement was performed with an electron microscope.

In the measurement pattern shown in FIG. 6, the line width of the isolated line pattern L1 and the line width of two or nine line patterns arranged in parallel can be measured. Of these, in FIG. 5, one of the two line patterns arranged in parallel has a resist pattern width L2E, and one of the nine line patterns arranged in parallel has one of the resist pattern widths L9E located at the end, The resist pattern width L9C located at the center of the nine line patterns arranged side by side is illustrated.

As shown in FIG. 5, the dimensional deviation increases as the pitch decreases. Further, the dimensional deviations are substantially equal in L2E and L9E, and L9C is larger than these. This is because the optical proximity effect affects only the opposite sides of the adjacent line patterns.
This is because in 9E, only one side is affected by the optical proximity effect, while in L9C, both sides are affected by the optical proximity effect.

As described above, the deviation of the line width due to the optical proximity effect is caused by the movement of the side adjacent to the pattern. Next, the underlying polycrystalline silicon film was etched using the resist pattern thus formed as a mask, and the dimensional deviation due to the optical proximity effect and the etching density effect was measured.

As shown in FIG. 7, the dimensional deviation is larger than the resist pattern width shown in FIG. That is, the pattern line width narrowed by the optical proximity effect is further narrowed by the etching shift during etching. Also, as the pitch decreases, the etching shift amount increases in the direction of becoming relatively smaller,
It can be seen that the etching density effect occurs.

The pattern shape after etching is shown in FIG. 8. Even in the result after etching, as in the case of the optical proximity effect, the phenomenon that the side on the side where the pattern exists is moved adjacently occurs. I understand. Therefore, the dimensional deviation due to the optical proximity effect and the etching density effect is that the sides are moved according to the mutual distance, so that on the photomask,
It can be seen that a value corresponding to this moved amount of change may be given in the opposite direction.

In the dimension deviation measurement after etching, for example, L1, L2E, L9E and L9 shown in FIG. 6 are used.
If the line width of C is obtained from the resistance value of polycrystalline silicon after etching (by four-terminal measurement) and the sheet resistance value, highly accurate measurement is possible. Next, an example of the mask pattern correction method according to the present embodiment will be described in consideration of the above results.

In FIG. 9, a WSi film of about 200 is formed on the base substrate.
When a resist (MCRPi7300 manufactured by Mitsubishi Kasei Co., Ltd.) having a film thickness of about 0.76 μm is coated on the wafer having a thickness of nm, and then exposed by i-line using a stepper with NA of 0.57 and σ of 0.6. 10 is a graph showing the relationship between the pattern pitch in the 0.34 μm pattern width and the dimensional deviation due to the optical proximity effect and the etching density effect, FIG. 10 is a diagram showing the deformation due to the deviation phenomenon of the transferred pattern, and FIG. It is a figure which shows an example of the photomask which corrected by the mask pattern correction method by an Example.

Now, under such optical conditions, as shown in FIG.
Consider transferring the mask pattern shown in FIG. The mask pattern shown by the solid line in FIG.
It consists of three line patterns 30, 32, 34 having a width of μm, and are arranged in parallel at an interval of 0.45 μm from each other in the upper part of FIG. Line patterns 32, 34
Are bent in the lower right direction from the vicinity of the center, and the three line patterns 30 and 32 are arranged so as to be parallel again from the position where the width is 1.25 μm.

As described above, the line pattern 32 and the line pattern 34 are always arranged at an interval of 0.45 μm, and the line pattern 32 and the line pattern 30 are
They are arranged at 0.45 μm intervals in the upper part and at 1.25 μm intervals in the lower part. Assuming that a pattern conforming to such a design pattern is formed on the photomask, dimensional deviations of the amount shown in FIG. 9 occur on the sides adjacent to the line pattern.

That is, at the place where the line patterns are arranged at 0.45 μm intervals, as shown in FIG.
A dimensional deviation of 17 μm occurs. Similarly, in the place where the line patterns are arranged at 1.25 μm intervals, about 0.
A step deviation of 004 μm will occur. For this reason,
A pattern as shown by the wavy line in FIG. 10 is formed on the wafer.

Therefore, based on the result of FIG. 9, it is possible to make the pattern formed on the wafer close to the design size by offsetting the pattern on the photomask in advance by an amount that causes the size deviation. Become. FIG. 11 shows the mask pattern after correction. In the mask pattern correction method according to the present embodiment, the area is divided into three,
Different offsets were provided in each area.

That is, in the first region 36 in which the distance between the patterns is 0.45 μm, 0.017 caused by the dimensional deviation is generated.
In order to prevent the line width from being reduced to .mu.m, an offset of 0.017 .mu.m is provided on each side adjacent to the pattern. In the second region 38 in which the distance between the patterns is 1.25 μm, offsets of 0.004 μm each were provided on the sides adjacent to the patterns in order to prevent the line width of 0.004 μm from being narrowed due to dimensional deviation.

Further, the distance between the patterns is from 0.45 μm to 1.
In the third region 40 changing to 25 μm, an offset of 0.011 μm, which is the amount of dimensional deviation corresponding to the average pattern distance of 0.85 μm of the region, is provided. By thus correcting the mask pattern, a pattern as shown by the dotted line in FIG. 11 is formed on the wafer, and it is possible to perform pattern formation in which the optical proximity effect and the etching density effect are suppressed.

As described above, according to this embodiment, the change in the pattern dimension due to the optical proximity effect and the etching density effect is
After preliminarily investigating based on the line width obtained from the resistance value of the electron microscope or the metal object to be etched and the sheet resistance, the mask pattern is formed by adding an offset according to the distance between the patterns on the sides where the patterns are adjacent. Since the correction is performed, it is possible to form a pattern in which the effects of the optical proximity effect and the etching density effect are suppressed.

In the above embodiment, when the adjacent patterns are not parallel to each other, the correction is made using the correction value corresponding to the average distance between the patterns. However, the correction may be made according to the distance between the patterns. However, the mask pattern may be corrected using a plurality of discontinuous correction values. However, when the correction is performed using the correction value corresponding to the average distance between the patterns, it is desirable that the correction data can be easily generated.

Further, in the above-described embodiment, the correction was made by previously providing the offset to the moving side due to the optical proximity effect and the etching density effect, but the line pattern 30 or 34 is indicated by the wavy line in FIG. In addition, an offset may be provided on the side opposite to the side that moves due to the optical proximity effect and the etching density effect, or the offset amount may be divided into two as shown by the wavy line in FIG. You may provide each offset.

Since the gap between the patterns is narrowed by providing the offset, if the space is too narrow, the resolution between the patterns may be deteriorated. However, if the offset is provided on the opposite side or is provided separately on both sides, the amount by which the pattern interval is narrowed can be reduced, so that the mask pattern correction can be performed without degrading the resolution between the patterns. .

Further, in the above embodiment, the mask pattern is corrected in consideration of both the optical proximity effect and the etching density effect, but the correction is performed in consideration of either the optical proximity effect or the etching density effect. May be. Further, the mask pattern correction according to the present embodiment may be added after the mask pattern correction according to another correction method.

The mask pattern correction method described above is
It can also be applied when forming a phase shift photomask. Further, in the above embodiment, the optical proximity effect,
The case where the pattern line width becomes thin due to the etching density effect has been described, but the same correction can be performed when the pattern line width becomes thick due to these effects.

For example, when a side shifts in a direction in which the side becomes thicker as the distance from the opposite side becomes larger, it is possible to perform correction by moving the side in a direction in which the side becomes thinner as the distance becomes larger. Further, in the resist pattern forming method using electron beam exposure, the correction value cannot always be determined only by the distance between the patterns due to the influence of electron backscattering and the like. However, if the mask pattern correction method according to the present embodiment is added to a correction method unique to electron beam exposure, such as a correction method that takes into account the pattern density conventionally used for electron beam exposure or thermal correction, a pattern that uses electron beam exposure is obtained. Also in the forming method, it is possible to correct the etching density effect and the like, and it is possible to improve the accuracy of the formed pattern.

The pattern forming method using electron beam exposure may be used when a pattern is directly drawn on the resist film on the wafer, or when pattern exposure is performed on the resist film on the photomask. .

[0062]

As described above, according to the present invention, when the first mask pattern and the second mask pattern arranged adjacent to the first mask pattern are formed on the photomask, , Due to optical proximity effect and etching density effect
Pattern correction data is created using the relationship between the dimensional deviation and the pattern pitch, and the sides of the first mask pattern are set to the first
Since the mask pattern is moved based on the correction amount corresponding to the distance between the second mask pattern and the second mask pattern, it is possible to prevent the pattern dimension from deviating due to the optical proximity effect and the etching density effect.

Further, when the first mask pattern and the second mask pattern arranged adjacent to the first mask pattern are formed on the photomask, an optical proximity effect is generated.
Dimensional deviation due to etching density effect and pattern pitch
And a first mask located on the side opposite to the first side of the first mask pattern located on the side of the second mask pattern. Since the second side of the pattern is moved based on the correction amount according to the distance between the first mask pattern and the second mask pattern, it is possible to prevent the deviation of the pattern dimension due to the optical proximity effect or the etching density effect. You can

Further, if the second side is moved or the correction amount is divided into the first side and the second side and then the second side is moved, the interval between the patterns due to the mask pattern correction is prevented from becoming narrow. Therefore, it is possible to prevent the resolution between patterns from deteriorating. In addition, in the above-described mask pattern correction method, if the first side or the second side is moved based on the correction amount according to the average distance between the first mask pattern and the second mask pattern, the two sides are adjacent to each other. Even when the mask patterns to be used are not parallel to each other, the mask patterns can be corrected.

Further, if the area on the photomask is divided into areas where the correction amount of the mask pattern is substantially equal and the mask pattern is corrected for each of the divided areas, the mask pattern can be accurately corrected. Further, in the above mask pattern correction method, the correction amount is determined by the masking of the dimensional deviation caused in the step of transferring the resist pattern onto the substrate using a photomask and the step of etching the substrate using the resist pattern as a mask. It can be obtained by measuring in advance as a function of the pattern interval.

Further, when the pattern is transferred onto the substrate using the photomask having the mask pattern corrected by the above-described mask pattern correction method, it is possible to prevent the deviation of the pattern dimension due to the optical proximity effect or the etching density effect. it can. Further, in a pattern forming method for transferring a mask pattern formed on a photomask on a substrate, if the photomask is used for exposure, a pattern with a small change in dimension due to an optical proximity effect or an etching density effect is formed. can do.

The first pattern and the first pattern are formed on the substrate.
Of the second pattern arranged adjacent to the pattern of No. 2 by the optical proximity effect and the etching density effect.
Pattern compensation is performed using the relationship between the dimensional deviation and the pattern pitch.
If the positive data is created and the side of the first pattern is exposed using the exposure data moved based on the correction amount according to the distance between the first pattern and the second pattern, the electron beam It can also be applied to a pattern forming method using a particle beam such as.

Further, if the pattern is transferred by the photomask having the mask pattern formed by the above-mentioned pattern forming method, it is possible to form a pattern having a small size deviation from the design size due to the optical proximity effect, the etching density effect and the like. .

[Brief description of drawings]

FIG. 1 is a graph obtained by simulating a change in light intensity due to an optical proximity effect.

FIG. 2 is a diagram (No. 1) showing a structure of a measurement pattern used in measuring an etching density effect.

FIG. 3 is a diagram (No. 2) showing the structure of a measurement pattern used in measuring the etching density effect.

FIG. 4 is a schematic diagram illustrating the definition of dimensional deviation in an example of the present invention.

FIG. 5 is a graph showing the relationship between the dimensional deviation due to the optical proximity effect and the pattern pitch.

FIG. 6 is a diagram showing a measurement pattern used when measuring the line width of the pattern.

FIG. 7 is a graph showing the relationship between the pattern pitch and the dimensional deviation due to the optical proximity effect and the etching density effect.

FIG. 8 is a diagram illustrating the deformation of the pattern shape after etching due to the separation phenomenon.

FIG. 9 is a graph showing the relationship between the pattern pitch and the dimensional deviation due to the optical proximity effect and the etching density effect.

FIG. 10 is a diagram showing deformation of a transferred pattern due to a separation phenomenon.

FIG. 11 is a diagram showing an example of a photomask corrected by a mask pattern correction method according to an embodiment of the present invention.

FIG. 12 is a diagram showing a mask pattern correction method according to a modification of the embodiment of the present invention.

[Explanation of symbols]

10 ... Silicon substrate 12 ... Silicon oxide film 14 ... Silicon nitride film 16 ... Resist pattern 18 ... α-silicon film 20 ... WSi film 22 ... Silicon oxide film 24 ... α-C film 30 ... Line pattern 32 ... Line pattern 34 ... Line pattern 36 ... First area 38 ... second area 40 ... Third area

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-60-74628 (JP, A) JP-A-8-314114 (JP, A) JP-A-7-74074 (JP, A) JP-A-6- 186724 (JP, A) JP-A 6-138643 (JP, A) JP-A 6-19115 (JP, A) JP-A 5-109850 (JP, A) JP-A 5-66550 (JP, A) JP-A-4-344644 (JP, A) JP-A-3-36549 (JP, A) JP-A-3-15065 (JP, A) JP-A-2-189913 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F 1/08 H01L 21/027

Claims (9)

(57) [Claims] 1. A mask pattern correction method for a photomask used when projecting and exposing a pattern on a substrate, comprising: a first mask pattern and a second mask which are adjacent to each other with a certain distance on the photomask. When forming a pattern, dimensional deviation and pattern due to the optical proximity effect and the etching density effect
Pattern correction data is created using the relationship with the turn pitch, and the side of the first mask pattern is moved based on the correction amount according to the distance between the first mask pattern and the second mask pattern. A method for correcting a mask pattern, which comprises: 2. A mask pattern correction method for a photomask used when projecting and exposing a pattern on a substrate, wherein a first mask pattern and a first mask pattern are arranged on the photomask and adjacent to the first mask pattern. When the second mask pattern is formed, the dimensional deviation due to the optical proximity effect and the etching density effect and the pattern
Create pattern correction data using the relationship with the turn pitch.
And a first side of the first mask pattern located on the second mask pattern side and / or a second side of the first mask pattern located on the opposite side of the first side. To
A mask pattern correction method comprising: moving based on a correction amount according to a distance between the first mask pattern and the second mask pattern. 3. The mask pattern correction method according to claim 2, wherein the distance between the first mask pattern and the second mask pattern is the distance between the first mask pattern and the second mask pattern.
A mask pattern correction method, which is an average distance from the mask pattern. 4. The mask pattern correction method according to claim 1, wherein the area on the photomask is divided into areas in which the correction amount of the mask pattern is substantially equal, and the divided areas are divided. A mask pattern correction method, characterized in that the mask pattern is corrected every time. 5. The mask pattern correction method according to claim 1, wherein the correction amount includes a step of transferring a resist pattern onto the substrate using the photomask, and a mask of the resist pattern. As a method of correcting a mask pattern, a dimensional deviation caused in the step of etching the substrate is measured in advance as a function of the distance between the mask patterns. 6. A photomask having a mask pattern corrected by the mask pattern correction method according to claim 1. Description: 7. A pattern forming method for transferring a mask pattern formed on a photomask onto a substrate, comprising an exposure step of exposing using the photomask according to claim 6. . 8. A pattern forming method for exposing a resist film formed on a substrate using a particle beam, comprising: a first pattern on the substrate; and a first pattern arranged adjacent to the first pattern. 2 is exposed, the dimensional deviation due to the optical proximity effect and the etching density effect and the pattern
Create pattern correction data using the relationship with the turn pitch.
And the side of the first pattern is moved based on a correction amount according to the distance between the first pattern and the second pattern to expose the substrate to the particle beam. A method for forming a pattern, which comprises: 9. A photomask having a mask pattern formed by the pattern forming method according to claim 8.